A textbook on the fundamentals of quantum mechanics, emphasizing the effects from electron angular momentum including spin. Sufficient historical context is provided to better explain the origins of several well-known concepts in quantum mechanics. For the serious student and researcher, full derivations of results are included, as well as a first time derivation and application of spin-dependent energy dissipation introduced and applied in several important technological areas including spin transfer torque, spin diffusion, and micromagnetics. For superconductors, a novel and thorough treatment is provided under the premise that the potential function originally introduced by Cooper is also spin dependent as evidenced more clearly today by experimental data. This enables more precise properties of the potential to be exploited, its connection to holes, and it is shown to lead directly to discontinuities in both heat capacity and electrical conductivity at critical temperature. Relativistic quantum mechanics is also fully derived from application of the special theory of relativity along with several consequences. For superconductors, the text introduces a relevant higher order correction from the Dirac equation to the theory of superconductors to demonstrate its impact. These topics and their unique presentations are found exclusively in this text on quantum mechanics.